MXF OP1a has a bunch of different codecs and you should know what you choose for export because they have different specifications for audio tracks. That said you can’t export only 14 tracks out of CS6. You’ll need CC.
[Joy Kawk] “That didn’t work, I even delete audio track 15 and 16,but the output file still got 16 audio channels….”
Can you deliver a file that has 16 audio tracks but the last two are empty?